Raster is a data format consisting of regular grids of values, usually stored in an image-like format.

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306 views

Unknown Coordinate System on old drawing

I work with many old civil engineering documents, and occasionally I'll need to georeference one which has coordinates pairs listed at many given points but does not list which coordinate system these ...
6
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3answers
819 views

Converting point data into a weighted raster

I am completely re-writing my question as i think it was quite confusing before: I have a number of different points, each point has a -z value. I need to create some sort of raster or a series of ...
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2answers
1k views

Creating shapefile of satellite image footprints?

I'm looking for a tool or a workflow to compute satellite image footprints, for a large number of images across directories, and produce a shapefile. Ideal work flow would be: fire up tool point to ...
4
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1answer
778 views

Can QGIS resample Rasters during display?

When I was using ArcGIS a user could resample a raster during the display (I think via layer properties under the display tab). This would smooth the appearance of the raster so it wouldn't appear ...
6
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1answer
508 views

In QGIS, how do I remove a band from a raster?

When I process a raster in QGIS it creates a second band. It appears that band has no useful data. I like to use the Raster Colours Tool and it will not accept a raster with anything more than on ...
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2answers
483 views

How sensitive is Landsat to atmospheric correction?

How important is it to correct Landsat for atmosphere, haze and convert DN to reflectance? What impact does it have on the results, say for many of the vegetation indices?
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2answers
890 views

Change output file type in QGIS georeferencer?

I have successfully georeferenced a raster file via the Georeferencer plugin (Georeferencer GDAL Version 3.1.9) in QGIS 1.7.0. However, I noticed that the output georeferenced raster file is in TIFF ...
7
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2answers
3k views

Modify raster layer display and symbology properties programmatically with arcpy or ArcObjects

I have over 1500 NITF files that I need to be able to modify the layer display and symbology of programmatically from within ArcMap. I need to set the properties outlined in red below: I've looked ...
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1answer
607 views

GeoTIFF raster layer, c#

We have a map rendering engine (renders from MapInfo Interchange Format). This engine uses Mercator Projection. Now we have to insert a raster layer (orthophotos of a city), we have GeoTIFF files with ...
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1answer
382 views

Taudem Resources

As I frequently deal with hydrology, I've heard Taudem mentioned quite a few times. I'm finding all sorts of information, but much of it is dated for use with previous versions. In addition, the ...
4
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1answer
754 views

How can I calculate the vertical distance to the nearest water?

Summary: I would like to create a raster where each cell contains the vertical distance to the nearest water (a decent approximation would be acceptable). The problem is that I'm not sure how to go ...
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3answers
677 views

Overlay polygons on raster colour map to extract area values for each colour within each polygon

Does anyone know an answer to the following: I have a set of polygons created as the MCP of animal movements. I also have a habitat colour map raster, with 13 different habitat types as different ...
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How Do You Remove No Data From A Raster (.sid)?

I have an Image.sid that has a white border which is No Data. I've tried using Clip Raster Tool with no success. I've also changed the symbology value for No Data to be transparent. I'd like to ...
6
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1answer
410 views

QGIS composer - How can I eliminate striping across transparent raster layers?

I have downloaded QGIS dev version 1.7.0-114 and I have come across some weird behaviour in the composer. I create a map with a hillshade and a transparent DEM ontop of it, pretty standard stuff. ...
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5answers
1k views

Is there a way to clip an image with the basic ArcView package (9.3)?

Is there a way to trim a geo-referenced air photo to an irregularly shaped boundary? I tried the clip tool shown in my attachment, but it didn't work. It looks as though the output extent field ...
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3answers
241 views

Trying to make the private land white overlay hillshade but

I'd like to have anyone's feedback on this draft map I created. Tried to make the private ownership white but since it's RGB is not near to 255. I've seen someone created this map similiar to it and ...
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2answers
2k views

Remove overlap in raster using ERASE command line?

I am trying to erase a raster and is there a erase command for the Raster side? I am using ArcGIS 9.3.1. I have 2 rasters that are in the Landcover and there is overlap in between and would like to ...
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3answers
647 views

Australian Topo Map GeoTIFFs

Does anyone know if Australian topo map GeoTIFFs are made available anywhere (preferably for free)? LINZ makes them available in New Zealand - http://www.linz.govt.nz/topography/topo-maps/index.aspx ...
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2answers
4k views

Convert x, y position in georeferenced image (with world file) to longitude, latitude?

What steps do I need to do in order to calculate longitude and latitude for a specific pixel in a georeferenced image? For example this image ...
6
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1answer
639 views

Is there a way to get the percentage of different landuse types upstream of a given point?

I'm a fairly novice GIS user and know just enough to get in trouble in a lot of cases. I am trying to look at the connection between several measured parameters at a few hundred stations along ...
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3answers
496 views

Point to Raster Issues

I am having some trouble with something fairly simple.. I am creating a 3D subsoil model for display in arcscene - i can get it displayed nicely as points but in order for the model to be easier to ...
3
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1answer
761 views

Cropping an image with a map extent

I have an raster file in my server space, which has the same projection as my webmap, and I would like to crop the image by passing the visible extent of a webmap. I think the cropping function is ...
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2answers
213 views

Setting Rasters to the exact same display

I have been tasked to make a series of .jpeg outputs of different sections of a dike displaying elevation data. My problem is that the data i have been given is GIGANTIC, almost the whole region made ...
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1answer
607 views

ArcGIS Desktop 10.0 — layout Data Frame Grid color inversion on export or print when other rasters are active

Having a problem with ArcMap 10.0 SP1 Data Frame Grid of graticule inverting color on export or when printing. Occuring on multiple classroom PCs all working with the same datasets. Exporting to ...
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2answers
1k views

JPG file all black when added as raster in QGIS

I add a new raster layer in the latest QGIS and select a JPG file, but it is all black. I tried adding the TIF version of the same image and that worked. What is it with the JPG, and how should I ...
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541 views

Raster to Vector

I want to map out moisture availability using satellite image but I do not know how to convert the raster image to a thematic map with limiting boundaries like state boundaries. I am using ArcGIS 9.3 ...
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2answers
1k views

Using Flex to display single rasters from raster catalog in ArcSDE/ArcGIS server

One of the front end develoeprs here is having issues displaying, or working out how to display a single raster held in a raster catalog in ArcSDE using the Flex 2.2 API the Raster Catalog holds ...
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3answers
744 views

ArcGIS- load multiple raster files from list

Good morning, Today's question is: how to select and load multiple rasters from one folder in Arc? My situation is probably familiar to some of you. I do have 3 folders with houndreds of maps in it. ...
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2answers
2k views

How do I calculate a weighted centroid with respect to a raster, e.g. population weighted centroid

In ArcGIS 10.0, how do I calculate the weighted centroid of a collection of polygons, where I want the weight to be a raster layer. In particular I am using a raster of population counts and would ...
6
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1answer
860 views

QGIS WKT Raster Plugin error, what does this mean?

I have been playing with the WKT Raster plugin. I have installed the WKT Raster experimental binaries in PostGIS successfully and followed the instructions in the read me to the letter. When i am in ...
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1answer
346 views

How to use r.patch with two maps having different colortables?

I am using r.patch to combine two raster maps in order to fill in the null values of the other. Is there a way to use r.patch but still maintaining the colortables of the separate raster maps? I do ...
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5answers
585 views

How to save a raster and vector into a single PNG file in GRASS?

I am trying to save a raster and vector into a PNG file. The vector is overlayed on top of the raster map. I was only able to save the raster file into a png using r.out.png but without the vector.
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How to return raster values based on polygon (shapefile) boundaries in QGIS?

How to return raster values based on polygon (shapefile) boundaries in QGIS? Is this an elementary question, because I am finding it hard....... Ideally I would like a neat workflow as I am likely to ...
6
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1answer
563 views

How to modify the colors of a raster map to use only one color in varying shades?

I have a raster map in GRASS containing elevation values. I want to display the elevation values in only one color (specificaly blue) but in varying shades of blue. I tried the options in r.colors, ...
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2answers
102 views

Where can I get an ocean shaded relief for Central America?

Does anyone know where I can get an ocean shaded relief for the Central American coast?
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0answers
307 views

16bit grayscale raster displays all black in Geoserver

I have a 16-bit raster (MrSID) that I want to display in Geoserver 2.0.2 but it is displaying as all black. If I create a new style similar to the default raster.sld but with graychannel element the ...
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5answers
45k views

What are Raster and Vector data in GIS and when to use?

What are raster and vector data in the GIS context? In general terms what applications, processes, or analysis are each suited for? (And not suited for!) In answering someone's question today, I ...
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1answer
249 views

Problem in r.resample

When I run r.resample to crop a map by using a vector and a mask, the resulting map has the same shape as the vector that I used but does not replicate (exactly) the portion of the raster map that I ...
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2answers
839 views

How to delete a base map in GRASS?

I'm trying to delete a map that I used as a mask before, but I cannot delete it using g.remove. It displays this: g.remove rast=raster_Mnorzagaray@PERMANENT [raster_Mnorzagaray@PERMANENT@PERMANENT] ...
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2answers
2k views

How to set the value of a pixel based on its current value?

I am attempting to set the value of a pixel based on its current value. I am using the Raster Calculator in Quantum GIS dev 1.7 trunk. For example, if the value is 0, I want to set it to 255. Based ...
7
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1answer
908 views

GRASS - Will r.to.vect work on this scanned map?

Total GRASS noob here. I have several very large hand contoured maps to digitize, and this thread intrigues me. In the past I have spent hours upon hours digitizing these maps and revisions in ArcMap. ...
2
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1answer
297 views

Two rasters created from the same polygon have different extents?

My problem is that i am trying to export some rasters to Rockworks so that i can create a sand layer from them. Rockworks requires the grid files i use to have the exact same XY co-ordinates. So i ...
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1answer
1k views

Count of raster cells as variable in arcgis 10 modelbuilder

I want to use a cell count of an integer raster as a variable in Arcgis 10 modelbuilder (and later in a python script), but can't seem to find how to access this information. Is there a (python) ...
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1answer
251 views

How to export a png file from a raster file? r.out.png has an error

I used r.out.png to export a png file, but it produced this error: (Sun Feb 27 00:26:32 2011) r.out.png input=raster_bulacanElevation ...
3
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1answer
754 views

Is there a way of cutting a raster map that is displayed in the GRASS GIS Map Display?

I have a raster map that I generated from cropping/masking from a bigger raster map. It produced a map with only a portion of not null values. I only want to have a map that is zoomed in to the ...
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2answers
3k views

Difference between Geoserver stores: ImageMosaic, WorldImage, ImagePyramid

What are the differences between the Geoserver stores ImageMosaic, WorldImage, and ImagePyramid? I noticed that ImagePyramid is no longer included in the latest Geoserver. Is one of these more ...
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1answer
419 views

Extract many or clustered cells attributes around points

My question is similar to Extract raster values at points, but perhaps more complex. How to extract the attributes of clustered cells around a point/points? For example, I have many vegetation plots ...
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3answers
2k views

R: Download a large DEM, change projection, and adjust to smaller scale

This is a process that takes just a few seconds in GIS software. My attempt to do it in R uses a large amount of memory then fails. Is there something wrong in my code, or is this just something R ...
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2answers
1k views

R: overlay a line on a raster stack/brick, and get profile of cell values along the line

I've combed through R's raster functions and vignettes and can't seem to get this working. I want to specify a line/vector across a raster stack (a DEM and possibly related variables), and get a ...
2
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1answer
179 views

gdalwarp results all black

I'm trying to convert a bmp image in BNG to WGS84 using gdalwarp (via QGIS). It seems to be running without errors but the output is all black. What am I doing wrong?